ELI5: In the UK, why are the majority of taxi drivers middle eastern?

Jobs like taxi driving, dry cleaning, motel management, and so forth, are commonly performed by immigrants because they don't require perfect fluency in the local tongue, and because they can provide a certain autonomy from low-level managers who might have racist views. Since BoscoBarry and andybhoy haven't seen the same predominance that you have, it seems likely that some taxi drivers are Caucasian and some are Middle Eastern, and the immigrant taxi drivers just stick out more to you, because there are roughly sixty four million people in the UK and only about 250k of them are of Middle Eastern descent!